Question

using MIPs assembly, ask the user to enter two numbers. Then multiply the two numbers using bit shifting (not 'mul'). This should work multiplying 2 positive numbers, 2 negative numbers, and a positive/negative number.

Then output the result and ask user if he/she has more calculations to complete.

Answer 1

product.asm:

.data
textout:.asciiz "please enter 2 numbers \n"
textout1:.asciiz "please enter 1st number: "
textout2:.asciiz "please enter 2nd number: "
textout3:.asciiz "The product of the numbers is: "
.text
main:
   li $s2,0 #result initialized too zero
  
   la $a0 textout #print prompt string
   li $v0 4
   syscall
  
   la $a0 textout1 #print prompt string
   li $v0 4
   syscall
  
   li $v0 5
   syscall
   move $s0,$v0
  
   la $a0 textout2 #print prompt string
   li $v0 4
   syscall
  
   li $v0 5
   syscall
   move $s1,$v0
  
   bltz $s0,a   #check if 1st number is negative if negative jump to a
   bltz $s1,b   #check if 2nd number is negative if negative jump to b
   j multiply

a:   bltz $s1,both #check if 2nd number is negative if both are negative jump to both
   li $t0,1   #flag = 1
   sub $s0,$zero,$s0 # make the 1st number positive
   j multiply
b: li $t0,1   #flag = 1
   sub $s1,$zero,$s1 # make the 2nd number positive
   j multiply

both:   li $t0,2   #if both numbers are negative
   sub $s0,$zero,$s0 # make the 1st number positive
   sub $s1,$zero,$s1 # make the 2nd number positive
   j multiply
  
multiply: beqz $s1,res
   andi $t1,$s1,1
   beqz $t1,add_s
   add $s2,$s2,$s0
add_s:   sll $s0,$s0,1
   srl $s1,$s1,1
   j multiply
  
res:   beq $t0,1,neg #if flag = 1 make result negative
   j end
neg:   sub $s2,$zero,$s2
   j end
  
end:   la $a0 textout3
   li $v0 4
   syscall
  
   move $a0,$s2   #print result
   li $v0,1
   syscall  
  
  
Output: